Final Drives Flashcards
One advantage to a final drive is
______________
it allows the other power train components to carry less load
One function of the sprocket shaft is __________________
to support the track frame
The type of reduction which may be inboard or outboard is the _________________
planetary drive
The simplest type of shovel drive is
________________
Chain
Planetary final drives are ____________
double reduction
Single reduction final drives use a ____________ system of lubrication.
splash
Mechanic A says that when you are draining the oil from a final drive, if you see any metal particles in the oil you must immediately overhaul the drive
Mechanic B says that all track machines must be jacked up and have the track frame removed in order to service the final drive
Who is right?
Neither is right
Before you begin to take a final drive apart you should ___________
wash the entire area thoroughly
Misalignment of gears will generally cause _______________
interference wear
Mechanic A says that bent axles can be straightened and reused.
Mechanic B says that the oil pump and filter should be serviced thoroughly when the final drive is serviced.
Who is right?
B is right
The advantage of a double reduction final drive is that it can provide a greater _________ to the sprocket in the same space as a single reduction gear drive can
torque
Lubrication for double reduction final drives can be either a ____________ or __________, depending on the size of machine and the manufacturer.
splash or a pressure feed system
A planetary gear system has two advantages. What are they?
- Performing a high reduction within a limited space
- Allowing the first reduction gears to carry less load and thus to be lighter (reduced gear width).
In a pressurized system, oil is picked up through a screen at the bottom of the housing by a ___________ driven by the _________. The oil flows through a full flow filter and is fed to all the vital areas requiring lubrication.
gear pump
idler gear
The three types of final drives used on crawler dozers, excavators and loaders are:
- single reduction final drives
- double reduction final drives
- planetary final drives
A single reduction final drive has one set of ___________
gears
A single reduction final drive has one set of gears. These gears are: ______________ and ______________
- the final drive pinion gear
- the final drive sprocket gear (bull gear)
Where are the final drive pinion gear and the final drive sprocket gear (bull gear) usually located?
They are usually contained in one- piece housing which is bolted to the steering clutch housing.
The intermediate pinion and gear set are splined together on the same shaft and are usually supported by ___________________
a large tapered roller bearing at each end
How is the preload adjustment set in an intermediate pinion and gear set?
Shimming the bearings
What is the difference between how double reduction drives are lubricated now, versus how they used to be lubricated?
Newer double reduction drives are pressure lubricated, older units use splash method
The final drive is the final stage in a series of reductions that begin at the ______________
engine flywheel
The final drive begins at the engine flywheel, flows through the __________ and ______ ends at the final drive (wheels or tracks)
torque converter
transmission
_____________ can be defined as a condition that occurs between the surfaces of mating parts that are subjected to high torque loads
surface fatigue
Which type of final drive would likely produce a relatively smooth, flat fracture pattern?
shock load
What indicates a fatigue type failure in the final drive gear components?
pitted and spalled tooth surface
What type of final drive failure can result in a component becoming blackened and discolored?
lubrication
In a final drive on a dozer, if a sun gear in the planetary final drive is driven and the ring gear is stationary, how will the planet piston carrier rotate?
In the same direction as the sun gear
What is backlash?
The clearance between the crown teeth and the pinion teeth
Which type of chain is used in grader final drives?
roller
What must be done to determine grader drive chain elongation dimensions?
Hang the chain from a hoist, attach a scale, and place the chain under tension
Where does the final gear reduction occur in a single reduction final drive on a bulldozer?
Pinion drive
What would indicate that the lube level in a dozer final drive housing was acceptable?
Oil level is exactly even with the bottom of the filler hole
When (at what temperature) is the correct time to drain the final drive oil during a regularly scheduled lube change?
At operating temperature
What is the main purpose of the final drive?
To increase torque and decrease speed
___________ are designed to support the weight of the machine and have to absorb the torque and shock loads at the wheels or tracks
final drives
What are the 3 types of drive systems?
- Planetary Drive
- Pinion and Bull gear
- Chain
What are two main causes of overheating?
Overload
improper lube
